"Tax on superannuations that go from neccessary living expenses...

"Tax on superannuations that go from neccessary living expenses to luxury sounds reasonable"

You really consider $1.6M in super to be providing a luxurious lifestyle? That equates to $80k pa based on the standard 5% earnings assumption. Factor in inflation over time and it's going to be hard to stay in front of inflation and maintain a reasonable standard of living over 25 - 30 years of retirement.